Convert search_engines_page (and search_engine-adder) to be compatible with Polymer 0.8.

chrome/browser/resources/settings/search_engines_page/search_engine_adder.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview 'cr-search-engine-adder' is a component for adding a new search
  * engine.
  *
  * @group Chrome Settings Elements
  * @element cr-settings-search-engine-adder
  */
-Polymer('cr-search-engine-adder', {
+Polymer({
+  is: 'cr-search-engine-adder',
+
   /** @private */
   add_: function() {
     if (!this.$.domainField.isInvalid &&
         !this.$.keywordField.isInvalid &&
         !this.$.queryURLField.isInvalid) {
       chrome.searchEnginesPrivate.addOtherSearchEngine(
           /* name */ this.$.domainField.value,
           /* keyword */ this.$.keywordField.value,
           /* url */ this.$.queryURLField.value);
       this.$.domainField.value = '';
       this.$.keywordField.value = '';
       this.$.queryURLField.value = '';
     }
   },
 });